Using somatic cell hybridization techniques, monoclonal antibodies have been prepared against two human malignancies, acute lymphoblastic leukemia (ALL) and ovarian carcinoma. Studies are proposed to examine the pharmacokinetics and toxicity of these reagents after intravenous or intraperitoneal infusion. Methods will be sought to utilize or to prevent antibody-induced modulation of antigens from the surface of ALL cells. Monoclonal antibodies will be used to eliminate leukemic cells from bone marrow before antigenic modulation occurs, facilitating effective autologous marrow transplantation. Attempts will be made to analyze the capacity of antibodies of different subclass to activate cellular or humoral effector mechanisms. The immunostimulant C. parvum will be administered to augment cellular effector function for antibody dependent tumor cell lysis. These studies should help to provide a more rational basis for the use of monoclonal antibodies for serotherapy of human cancer.